I find there are little changes between updates. If I would have to spend money, I would buy an update once year or year and a half.
It's a pity you have a Via, otherwise you could get all TomTom maps for free.
With Megaupload having been intervened by the USA authorities, most of the other Rapidshare like up/download sites are closing their servers in fear of following the same fate. There are still a few around but they better watch out!
With many units now offering free lifetime updates, it is generally not worth it to buy updates. Spend a few more dollars every few years and you can buy a new unit with more features. For example there was a 5 " TomTom on TigerDirect within the last few days with free lifetime map updates for $80. Same price for the map updates the OP quoted.
I guess the $64 question is: are they necessary, how often,... How do I check whether I need one.
I go to a reasonably uptpodate paper maps etc etc find the most obscure st them navigate to it on my GPS to it!!
If its in there I'm up to date!!
I live in Belgium and personally I don't think it is worth the money. My XXL is two years old now and I haven't had a single problem. It might be better as other posters say to buy a new unit every few years after selling the old unit.
It depends how important driving is to you. For a courier, you'd probably need current maps. The average domestic (non business) driver could easy get away with never updating. Only if you want to find people in new streets you'd need to update. However I did pay for a map update for my 3-4 year old 720 recently and got the map - and a system update as well.
I recently paid for another 18 months of map updates, all went well.
I then asked for a refund of the VAT, as I heard this was possible.
TOMTOM seem to have given me a full refund, so now I don't know if I have a subscription or not.